A device which calculates the potential risk degree around a vehicle so as to increase traveling safety has been suggested. For example, Patent Literature 1 discloses a minimum risk locus generation device which detects a road shape and obstacles and calculates a minimum risk traveling locus, and an endangerment warning device using the same.
The endangerment warning device of Patent Literature 1 includes an obstacle detection radar, a white line detection camera, a traveling state detection sensor, and a CPU. The CPU acquires information relating to an obstacle from the obstacle detection radar, and acquires the road shape and the traveling position of the host vehicle from the white line detection camera. The CPU also acquires vehicle speed data and the operation situation of a direction indicator from the traveling state detection sensor, and acquires road information from a navigation device.
The CPU estimates a traveling route in a traveling route estimation unit on the basis of the acquired information, and sets the value of the risk degree at each point on the road in a risk degree setting unit. In this case, the surroundings of the vehicle are divided into a virtual mesh (lattice-shaped regions), and the value of the risk degree in each lattice is calculated. The CPU calculates the minimum risk traveling locus, in which the total risk degree is minimal, in a minimum risk locus calculation unit. When the risk degree on the minimum risk traveling locus exceeds a warning threshold value, a determination unit of the CPU outputs a warning to a display device and a speech device.